Starting from 1 January 2025, companies in Germany will be required to issue and receive electronic invoices in accordance with the EN 16931 standard. This particular e-invoice is the digital format for invoices that enables automated and standardised delivery. It aims to increase tax transparency, optimise business processes and reduce errors – however, the most important prerequisite for this is reliable delivery. Email is a widely used delivery channel for e-invoices, which makes deliverability via this medium a particular focus for many companies.
Mandatory e-invoicing: Companies must take action
The shift to electronic invoicing brings numerous advantages:
- Increased efficiency: Automated invoicing processes reduce administrative effort and accelerate payment transactions.
- Error reduction: Standardised formats prevent transmission errors and facilitate processing.
- Tax transparency: Digital documentation makes tax audits more transparent and manageable.
- Sustainability: Eliminating paper invoices reduces resource consumption and cuts costs.
However, it is essential that IT systems are compatible and ensure the smooth processing of e-invoices.
Optimising email deliverability as a success factor
Not only in B2B, but also in B2C sectors, companies are faced with the challenge of ensuring that their invoices are delivered reliably by email. This is because consumers could also miss important invoice documents if they are blocked by spam filters or end up in the spam folder.
However, the efficiency of electronic invoicing depends largely on emails reaching the recipient reliably. A common problem is that invoice emails are blocked by spam filters or moved to the spam folder. This is where the Certified Senders Alliance (CSA) comes in: by establishing standardised procedures and guidelines, CSA helps improve the deliverability of business emails. The CSA’s Certified IP List ensures that trusted senders are recognised and that their emails are delivered preferentially.
The Certified IP List is a list of trusted IP addresses that have been certified by the CSA. Many international mailbox and spam filter providers rely on this list to distinguish legitimate senders from potentially harmful or unwanted emails. By being included in this list, companies benefit from improved inbox delivery rates, fewer delivery issues and faster email processing.
Measures to improve deliverability:
- Email authentication: The use of SPF, DKIM and DMARC* helps to authenticate emails correctly and confirms they originate from a trusted sender. These protocols also protect against abuse, such as spoofing, and increase the likelihood of emails being classified as trustworthy instead of spam.
- Use of Certified Service Providers: These providers ensure legally compliant and technically clean delivery, meet recognised standards and – thanks to their CSA certification – have a high delivery reputation with mailbox providers.
- Clean technical structure: Clearly structured HTML code without unnecessary formatting reduces technical errors, improves presentation and increases acceptance by spam filters.
- Clear sender & consistent domain: A recognisable sender address (ideally with a company domain) and a clear name build trust and reduce the chance of being flagged as spam.
- Neutral content without marketing language
- Use a feedback system: Feedback on spam complaints or authentication errors helps to identify problems early on and take countermeasures. With the CSA’s Certification Monitor, companies can directly access and analyse feedback from mailbox providers to continuously improve email deliverability and quickly resolve any issues.
The obligation to use e-invoicing represents a significant change, but at the same time offers opportunities for digitalisation and process optimisation. High deliverability of invoice emails is an essential factor for the successful implementation of this innovation. The use of standards and lists ensures that business emails are delivered securely and are not lost through spam filters. Through targeted measures to optimise email communication, it can be ensured that digital invoices are transmitted efficiently.
- *SPF (Sender Policy Framework): SPF is a method that specifies which servers are allowed to send emails on behalf of a domain in order to detect forged senders.
- DKIM (DomainKeys Identified Mail): DKIM adds a digital signature to emails that allows the recipient to verify whether the message really came from the sender and has not been altered in transit.
- DMARC (Domain-based Message Authentication, Reporting and Conformance): DMARC builds on SPF and DKIM and gives domain owners the ability to determine how receiving servers should handle non-authenticated emails – for example, reject them or move them to spam.
